Tactile touch technology localises multi-finger HMI contacts, simulates textures

July 15, 2014 // By Graham Prophet
A tactile touch display enables multiple users to individually feel the texture of the image they touch.

NLT Technologies (NLT), together with its sales and marketing channel in Europe, Renesas Electronics Europe, has announced an LCD prototype that incorporates a tactile touch feature. This technology recreates the sense of tactile texture to the users by using vibrations and reproduces skin sensations as if they are tracing actual objects on the display.

The display provides texture via skin sensation when the user traces the surface of the display where the image is shown. If multiple fingers touch the display at the same time, the digits on the area where the image is shown can feel the appropriate texture, but the digits on the area without the image will not feel the texture. This enables users to identify which area on a display the image is shown, not only visually, but also through tactile feel.

The stimulus can be localised in conjunction with the image object, enabling each finger to sense its own stimulus, so the display can accommodate multi-finger or multi-person tactile interaction with visual information.

A conventional tactile touch system presents the same sensation over the entire surface so that all fingers coming into contact with the surface experience the same sensation. In contrast, the new NLT tactile touch technology provides regional stimulation, which is provided by electrostatic force. The electrostatic force is generated by the beat phenomenon in a region where excited X electrodes cross excited Y electrodes, which presents tactile sensation to the users.

The display arranges multiple electrodes horizontally (X) and vertically (Y) on the glass panel and applies voltage with different frequencies to each X and Y electrode located on the image area. Electrostatic force corresponding to the difference in the frequencies occurs at the electrodes' cross point. When user traces on the surface, friction variation, modulated by the electrostatic force, occurs. The display uses this friction variation to provide the tactile sensation. The friction variation does not occur at the areas without